Does anyone know if there has ever been any consideration within RouterOS history of a mechanism where, acting as a BNG, RouterOS would create per-MAC virtual sub-interfaces?
Something similar to what is found in practically all other BNG vendor implementations, as well as in open-source projects.
I had hoped that "PPPoE over VLAN Range" would evolve into a Dynamic Interface VLAN Demux type of solution, but it seems that isn't the direction being taken.
I am looking for a way to place IPoE clients into different VRFs.
With PPPoE, it’s easy! You basically use a profile for each VRF, apply the VRF's interface list to that profile, and everything works!
However, with IPoE, I haven't been able to achieve a setup where the client is truly bound to a different VRF.
This would likely offer the advantage of enabling per-sub-interface queuing.
What you're asking for is not a general IPoE requirement. It's a particular BNG subscriber-management model, similar to traditional Juniper and Cisco BNG designs.
A per-MAC virtual sub-interface is even more implementation-specific. MAC address is only one possible way of identifying the subscriber; it isn't what defines IPoE.
IMO, a much cleaner, easier and more modern approach is to use VLAN/QinQ for subscriber separation, Option 82 for identification, and let the BNG handle AAA, policy, QoS and routing.
Per-subscriber virtual interfaces just add unnecessary complexity unless you specifically need different VRFs on a shared access VLAN, which I'd consider an edge case and something a properly designed FTTH access network should normally avoid in the first place.